I have KDE installed on Redhat 6...
It says installed correctly
But when I type in KDE I get:
kcontrol: cannot connect to x server
I get this a dozen times for different processes then back to $ prompt...

Mandrake 6? Red Hat 6? For the love of God, man! Where are you getting these old distributions?!?!?!?!

You're asking for nothing but trouble with those old versions. If you have broadband, you'll want to download a newer version. Your best bet would be to check out a place like CheapBytes to order some newer versions.

(FYI, Mandrake is up to 10.1, so there's a HUGE difference in your experience ahead of you.)

It will work as long as you compile the drivers correctly, most likly the XFree86 Engine is not configured to work with your video card, or your video card driver is not installed, and the generic ones back then sucked.